TLR4 and chronic obstructive pulmonary disease: As a bioactive compound extracted from houttuynia, sodium houttuyfonate (SH) significantly alleviated the pulmonary inflammation via suppressing the TLR4/NF-κB pathway, thus protecting the lung tissue on the CS-/LPS-induced mice model with COPD (Wu et al., 2017), and schisandrin B, a dibenzocyclooctadiene derivative identified from Schisandra chinensis, was reported to fight against CS-induced lung inflammation in mice by activating the Nrf2 and inhibiting NF-κB signaling pathway (Jia et al., 2017).